This invention relates to an annular fluid type pusher which is mounted on a shaft to fasten a part set on the shaft and has a pressing piece for pushing the part with fluid pressure, and a fluid pressure adjusting section.
FIG. 5 shows an annular fluid type pusher which is a prior development of the present Applicant. The fluid type pusher of FIG. 5 is mounted on a shaft to fasten a part on the shaft and has a pressing piece 16 for pressing the part with fluid pressure, and a fluid pressure adjusting section 13 for adjusting the fluid pressure.
The fluid type pusher 11 is mounted on a shaft on which a part is set, and then it is secured with a nut. Under this condition, a pushing screw 14 in the fluid pressure adjusting section 13 is screwed in with a torque wrench 12 fitted with a gauge (hereinafter referred to as "a gauge-fitted torque wrench 12", when applicable) to push a pressurizing piston 15 inwardly thereby to increase the fluid pressure in the fluid type pusher 11. As a result, the pushing piece 16 set between the part and the pusher 11 is moved towards the part to fasten the latter.
The gauge-fitted torque wrench, which is a precision tool, is expensive. Furthermore, it is liable to be broken when shocked. Hence, it must be handled with great care. Thus, it is rather troublesome to use it at the working site.
In the gauge-fitted torque wrench, the torque gauge is limited in the range of graduations. Hence, in the case where it is required to adjust the thrust of the pushing piece in a wide range which is adapted to push the part with fluid pressure, it is necessary to use a plurality of gauge-fitted torque wrenches.
The gauge-fitted torque wrench is a torque gauge. Therefore, in order to obtain a thrust value which is actually required for the pushing piece adapted to push a part with fluid pressure, it is essential to perform a mathematical conversion, which makes it rather troublesome to handle the gauge-withfitted torque. On the other hand, the coefficient of friction of the fluid pressure adjusting section depends on the finish accuracy of the threaded portion of the fluid pressure adjusting section, and therefore the value obtained through the conversion may be different from the actual thrust value.
Accordingly, an object of this invention is to eliminate the above-described difficulties accompanying a conventional fluid type pusher. More specifically, an object of the invention is to provide a fluid type pressure with a thrust indicator in which the thrust of the pushing piece adapted to push a part with fluid pressure is readily detected by reading a thrust measuring bar which is protruded in proportion to the fluid pressure, thus eliminating the use of an expensive gauge-withfitted torque wrench.